亚洲玉米螟对几种杀虫剂的敏感性测定

Sensitivity of Ostrinia furnacalis to several in secticides

为明确杀虫剂对亚洲玉米螟幼虫的毒力,采用浸虫法测定了亚洲玉米螟3龄幼虫对4种杀虫剂的敏感性。结果表明药剂处理24 h后,毒力指数大小顺序为45%毒死蜱EC>40%辛硫磷EC>5%氯氰菊酯EC>15%阿维·三唑磷EC,致死中浓度(LC50)值分别是42.729、56.839、106.688和933.447 mg/L;药剂处理48 h后,毒力指数大小顺序和24 h相同,LC50值分别是20.536、31.461、32.410和202.144 mg/L;处理72 h后,毒力指数大小顺序为5%氯氰菊酯EC>45%毒死蜱EC>40%辛硫磷EC>15%阿维·三唑磷EC,LC50值分别是10.072、11.881、12.825和39.568 mg/L。因此,可选用低毒的45%毒死蜱EC和5%氯氰菊酯EC来降低田间亚洲玉米螟虫口密度。

To determine the toxicity of commonly used insecticides,the sensitivity of the Ostrinia furnacalis 3rd instar larvae to four insecticides was determined by impregnation method.The results showed that when treated 24 h,their toxicity to the 3rd instar larvae were in the following order:45%chlorpyrifos EC>40%phoxim EC>5%cypermethrin EC>15%abamectin·triazophos EC;the median lethal concentration(LC50)values were 42.729,56.839,106.688 and 933.447 mg/L,respectively.When treated 48 h,their toxicity were same same as that of 24 h,and LC50 values were 20.536,31.461,32.410and 202.144 mg/L,respectively.When treated 72 h,heir toxicity to the 3rd instar larvae were in the following order:5%cypermethrin EC>45%chlorpyrifos EC>40%phoxim EC>15%abamectin·triazophos EC;LC50 values were 10.072,11.881,12.825 and 39.568 mg/L,respectively.Therefore,the low toxicity of 45%chlorpyrifos EC and 5%cypermethrin EC could be selected to reduce the population density of O.furnacalis in the field.